b ON SHOOTING STARS. 



visible to observers under them. The proportion rendered invisible depends also upon the 

 relative numbers of shooting stars of different magnitudes. Thus as an extreme case suppose 

 all were of equal brilliancy, and at an equal height above the earth. Above a certain 

 almacantaral circle we should see them all, while below that circle we should see none. 



The law of distribution of the paths in apparent altitude might be obtained directly by 

 observations arranged for that purpose. But such observations would have to be continued 

 for a considerable time, and would involve great labor. Another method has, therefore, been 

 adopted for obtaining the approximate law of distribution, by using materials collected for 

 other purposes. 



If we should compute or measure the zenith distances of a large number of paths seen by 

 one observer we should find them affected by his habits of watching. Thus one who looked 

 habitually to the zenith would see only those near that point, while one looking low down 

 would see few near the zenith. But combining the observations of a large number of persons, 

 we might hope that many of these individual habitudes would counteract each other, and that 

 the aggregate results would be affected only by common errors. I have therefore taken for this 

 purpose various sets of observations made by about forty different persons. Some are given 

 in the Astronomische Nachrichten, some in Quetelet's Correspondence Math, et Phys, some in Heis' 

 Wochenschrift, and some, not yet published, were made in this country in August and 

 November last. For a part, the distances of the middle points of the several paths from the 

 zenith for the time were computed. For the remainder, the place of the zenith was in each 

 case computed, and the distance from it to the middle of the path was carefully measured on 

 a good sixteen-inch globe. The number of paths thus computed, or measured, was 1,393. Of 

 these, 30 were within 10° of the zenith, 60 were between 10° and 20° from the zenith, 142 

 between 20° and 30°, &c, as in the second column of the following table: 



Table II. — Illustrating the distribution of meteor-paths over the shy. 



(29n) 



